Small Edit to Animation

I am looking for someone to take a single animation which is already complete, and edit the location and rotation of two or three bones such that the animation fits more correctly. I have an animation of a 3d character reloading a rifle, and the butt of the weapon is running into the shoulder of the character. I would like the character's arms rotated slightly to the left over the entire animation so that the gun fits correctly against the character's shoulder, and not clipping through it. The rifle animations don't need to be edited, but I will share those for reference to help positioning.